The article discusses recent research on the effective and safe use of the amino acid L-arginine for medicinal purposes in various pathologies. The practical significance of using L-arginine as a source of nitric oxide is considered. The physiological role of nitric oxide, the main vasodilator, was shown, and its deficiency was found to be a key link in endothelial dysfunction. An analysis of modern studies confirming the effectiveness of L-arginine as a donor of nitric oxide was carried out. Ample evidence suggests that oral administration of L-arginine, within physiological limits, can benefit human health by increasing NO synthesis and hence tissue blood flow.